This invention relates generally to a refrigeration system and particularly to a system for maintaining the condenser in a clean, dirt-free and lint-free condition.
Refrigeration systems which include a compressor, a condenser coil, and an electric motor driven fan for blowing air on the condenser coil suffer from reduced efficiency as the condenser coil collects dirt and lint over time. Because of this reduced efficiency it is necessary to subject the condenser coils to periodic cleaning resulting in down time of the system and in some cases costly repairs.
Various cleaning systems have been used in an attempt to obviate this problem. In particular, attempts have been made to eliminate the collection of lint and dirt resulting from the continuous blowing of air in one direction over the condenser by reversing the direction of the air stream over the condenser to blow collected lint and dirt off the condenser. The patents discussed below which relate to this problem are incorporated by reference herein.
An early patent which utilizes this principle of air stream reversal is U.S. Pat. No. 1,967,019 which discloses a fan arranged to blow cooling air through a condenser. Reversal of the fan motor, a single phase induction motor, is accomplished by changing polarity of the current in the starting winding. A solenoid pawl and cam arrangement is used to operate the switching. The solenoid operates a reversing switch and is actuated by energization of the compressor motor.
U.S. Pat. No. 2,525,462 discloses air flow reversal through a condenser in a refrigerator which is accomplished by a switching arrangement controlled by a modified compressor motor circuitry so that the fan direction is reversed each time the refrigerating unit stops and starts so that the fan operates in reverse when the refrigerating unit is idle. U.S. Pat. No. 3,344,854 discloses an anticlog device for automobile radiators which provides a movable endless belt screen such that foreign matter deposited on the screen when the belt is on to one side of the radiator is blown off the screen when the belt is moved to the other side of the radiator. U.S. Pat. No. 5,050,667 discloses a ventilation system in which a fan is pivotally mounted in a duct for rotation from a first position blowing air out of one end of the duct to a second position blowing air out of the other end of the duct. U.S. Pat. No. 5,226,285 discloses a self-cleaning fan assembly in which a reversible fan is located between two condensers and reversal is effectuated by means of pressure switches so that an increase in refrigerant flow reverses the rotation of the fan motor. These systems tend to be complicated, to operate at a constant cleaning speed and suffer from a lack of control of the operation and cleaning speed and operate in reverse for relatively uncontrolled time periods. In addition, these system do not offer flexibility in the choice of cleaning duty cycles, choice of fan speed in cleaning cycles, and require fairly complicated electromechanical devices which reverse air flow to the detriment of equipment reliability.
The present reversible fan arrangement solves these and other problems in a manner not disclosed by the known prior art.